160 THE FISH AND FROG 



ferent adaptations. Watch the fish carefully and locate its organs 

 for movement. How many single fins are there? How many 

 paired fins? 



Note. — Fins on the upper side of the body are called dorsal fins, the tail fin 

 is called the caudal fin, and the single fin on the lower side is the anal fin. The front 

 paired fins are called the pectoral fins, while those just below and behind are called 

 the pelvic fins. 



Try to discover the use in movement of each of the above- 

 named fins. 



Conclusion. — 1. How does a fish move? Watch the fish 

 swimming and try to decide what fins are used in moving forward, 

 in turning, in moving backwards. Note whether the body is used 

 in locomotion. 



2. Tell just how any particular fin is adapted or fitted to do its 

 work. (Remember you must show how a structure is especially 

 designed to do a particular work.) 



3. How is the body fitted for life in the water? 



b. Protection 



Method. — Examine carefully a preserved specimen. 



Observations. — What structures do you find on the surface of 

 the body? How are these structures placed with reference to 

 each other? Feel the body of the fish. What adaptation for 

 protection exists here? Note the color both above and below. 

 Remembering that many of the enemies of the fish are below him 

 and some above, explain how the animal receives protection from its 

 color. 



Conclusion. — What are the principal adaptations for protec- 

 tion in the fish ? 



c. Breathing 



Method. — Look at the fish carefully and observe the move- 

 ments of the mouth. 



Observations. — What is the relation of the movement of the 

 mouth to that of the operculwn, the flap which covers the gills? 

 Note position and color of the gills. What gives them this color? 

 Introduce a few grains of carmine in the water in front of the 

 mouth of the fish. Trace the course of the carmine. Where does it 



